The present invention concerns a device for supporting bony structures. In particular, the present invention device is directed to an end cap for use with a device for supporting bony structures.
The repair and reconstruction of bony structures is sometimes accomplished by directly fixing adjacent bony structures to each other, such as by a plate. In other instances, bone growth inducing material can be introduced between the adjacent bony structures, which over time results in a solid bony connection. In some instances, the adjacent bony structures are not sufficiently strong to maintain their patency as the bone heals or the bone grows between the adjacent structures through the bone growth inducing material. In these instances, mesh structures or cages have been provided to engage the adjacent bony structures to provide additional stability. The cages are generally hollow and can be configured to contact the harder cortical bone of the adjacent bony structures. The hollow portion of the cages can be filled with bone growth inducing material. One problem, among others, with cages and other devices inserted between adjacent bony structures is that the device can subside into the adjacent bony structure.
In one aspect of the invention, a device for supporting weak bony structures is provided. The device includes a body having a first end and a second end for contacting a bony structure. The body has a wall that defines a hollow chamber. An end cap is provided with opposite upper and lower surfaces, and includes a plurality of arms extending from a central ring. Each of the arms having a first end connected with the ring and an opposite second end including an outer surface. Each of the outer surfaces are positionable adjacent the inner surface of the wall of the body when the end cap is inserted into the hollow chamber. Each arm can also include a projection that extends at least partially into one of the wall openings.
In one form, bone growth inducing material in placed into the hollow chamber and a second end cap secured to the other end of the body.
According to another aspect of the invention, a device for supporting weak bony structures is provided. The device includes a body having a first end and a second end for contacting a bony structure and a wall extending therebetween. The inner surface of the wall defines a hollow chamber. An end cap is placed in the hollow chamber adjacent one end of the body. The end cap has a central ring and a plurality of curved arms extending from the ring to contact the body and secure the end cap in the hollow chamber.
In one form, the arms have a first end connected with the ring and an opposite second end having an outer surface for contacting the body. In another form, the outer surfaces of the biased arms form a perimeter extending around an inner portion of the end cap and the second end of each arm is deformable towards the inner portion. In another form, the second end of each arm includes a projection that is received in opening formed in the wall of the body.
According to another aspect of the invention, a device for supporting weak bony structures is provided. The device includes a body having a first end and a second end for contacting a bony structure. The body has a wall with an inner surface extending around a hollow chamber. An end cap is placed in the hollow chamber adjacent one of the ends of the body. The end cap has a plate member with opposite upper and lower surfaces defining parallel planes. The end cap has a plurality of arms deformable generally within these planes from a pre-insertion configuration to a reduced size configuration for insertion of the end cap into the hollow chamber. The plurality of arms are biased from their reduced size configuration to their pre-insertion configuration to contact the wall and maintain the end cap in the hollow chamber.
It is one object of the present invention to provide a device for supporting weak bony structures that includes a chamber for receiving osteogenetic material. A further object resides in features of the device that provide a strong structure that can readily engage adjacent bony structures. Another object is to provide a device for supporting weak bony structures that resists subsidence of the device into the adjacent bony structure.